Supercritical fluid extraction combined on-line with cold-trap gas chromatography/mass spectrometry

On-line coupling of a supercritical fluid extraction (SFE) system with a gas chromatography/mass spectrometry (GC/MS) instrumentation was performed by a home-made suitably shaped accumulation cell. This coupling eliminates the effect of CO2 flow on the MS detector, and considerably reduces the effect of high boiling compounds on the Chromatographic efficiency in the determination of organic pollutants in environmental samples. Moreover, it enables multi-step extraction based on the addition of the CO2 modifier directly into the extraction cell. In particular, a three-step extraction of some selected polycyclic hydrocarbons (PAHs) from harbour certified marine sediment reference material was performed at 70 °C extraction temperature, 20 MPa extraction pressure, 400 μl min−1 supercritical CO2 flow for a total extraction time of 15 min (i.e. 5 min for each extraction step), and showed recoveries between 80% and 100% for all PAHs considered with a coefficient of variation of about 10%.